Ventilation system for rotating electrical machinery



1968 v. B. HONSINGER 3,

VENTILATION SYSTEM FOR ROTATING ELECTRICAL MACHINERY Filed Feb. 21, 1966 2 Sheets-Sheet 1 1968 v. B. HONSINGER 3,407,317

VENTILATION SYSTEM FOR ROTATING ELECTRICAL MACHINERY Filed Feb. 21, 1966 2 Sheets-Shgei 2 United States Patent 3,407,317 VENTILATION SYSTEM FOR ROTATING ELECTRICAL MACHINERY Vernon B. Honsinger, Cincinnati, Ohio, assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Filed Feb. 21, 1966, Ser. No. 529,079 Claims. (Cl. 31058) This invention relates generally to dynamoelectric machines and more particularly to an improved ventilating system for dynamoelectric machines.

In our present society, electric motors are perhaps the main source of providing rotary motion to perform work. There are many motor manufacturers producing hundreds of different sizes and types of motors to satisfy the varied requirements of modern industry. Competition between these motor manufacturers is extremely keen and all are continually searching for means to improve their products and reduce costs.

Automated manufacturing procedures produced both product improvements and manufacturing cost reductions. However, motor designs limit the extent to which automated procedures can be utilized.

A more comprehensive approach to the cost problem is to design a motor in a manner to cut down the amount of material used and simplify the manufacturing procedures involved. One of the more expensive manufacturing procedures is the foundry casting of the motor yoke or frame. The frame casting which is used by a number i of the motor manufacturers includes a side ventilation air discharge port at the center of the motor frame. These side ventilation ports require a foundry practice using lard baked sand cores which are destroyed in the shake out after each pour. If this high cost foundry practice can be overcome, a large step is taken toward reduced cost in the manufacturing procedure. However, it has been found through prior experience that a ventilating system uti izing side air ports is one of the more preferred ways of adequately cooling the motor. One important reason why side ventilation ports are preferred is that adequate ventilation can be maintained without increasing the air velocity to a point Where it creates noise problems. With end ventilation, high velocity air is quite frequently required for properventilation. In many applications, this high velocity air results in a higher noise level which is unacceptable.

Furthermore, any design which reduces the amount of rnaLerial put into the motor also increases the heat transfer problems. As less iron is used, more air or at least a more efiicient ventilation system is required to dissipate the heat produced by the motor. It therefore becomes apparent that in order to decrease the cost of material and manufacturing procedures for an electric motor, a proper ventilating system becomes a prime concern.

It is therefore the general intention and main object of this invention to provide a ventilating system for a dynamoelectric machine which is more efficient than previously known ventilating systems.

An additional object of the subject invention is to provide a ventilaing system for a dynamoelectric machine wherein the cooling air is drawn in and exhausted from both ends of the motor frame.

A more specific object of the subject invention is to provide a ventilating system for a dynamoelectric machine wherein a portion of the air is drawn in and exhausted from the same end of the dynamoelectric machine frame as well as having a portion travel longitudinally from one end of the frame to the other.

These and other objects of the subject invention will become more fully apparent as the following description is read in light of the attached drawing wherein:

Patented Oct. 22, 1968 of the motor;

FIG. 5 is a perspective view of a bafile utilized in the ventilating system of the subject invention; and

FIG. 6 is a partially exploded perspective view of the motor.

Referring to the drawings, the invention is herein shown in connection with a motor having a cylindrical frame 6. A plurality of stator laminations 7 are stacked and connected to the interior of the motor frame 6 in any conventional manner which is well known in the electric motor art.

The configuration of the stator laminations contribute to the improved ventilating qualities of the motor. As best shown in FIG. 4, the stator laminations 7 are in effect circular disks having flats 8 cut on the outer peripheral surface thereof. These flats coact with recesses 15 in the inner peripheral surface of the motor frame to provide air passages 10 to insure proper ventilation of the motor as will be described more fully hereinafter.

Opposite ends of the cylindrical motor frame 6 are closed by end closures generally designated 9 and 11. These end closures may be connected to the frame in any conventional manner such as by throughbolts 12 from one end closure to the other, clamping them into engagement with the motor frame. Each end closure is provided with a centrally located bearing orifice in which are received shaft bearings herein shown as conventional ballbearings 13 and 14.

Rotatably supported within the stator laminations 7 is a rotating member or rotor generally designated 16. This rotor is provided with shaft extensions 17 and 18 respectively, journaled in the ballbearings 13 and 14. For purposes of illustrating the subject invention, a plurality of circumferentially spaced longitudinally extending fan blades 19 and 21 are cast integral with the rotor 16 on opposite ends thereof. Referring now to FIGS. 2 and 3, each end closure is provided with intake and exhaust openings. The front end closure 11, shown in FIG. 3, includes a pair of intake openings 22 and a pair of exhaust openings 23. The rear end closure 9, shown in FIG. 2, is also provided with a pair of intake openings 24 and a pair of exhaust openings 26. It should be noted that the intake openings 22 and 24 in opposite end closures are on opposite sides of the center line of the motor frame when viewed from either end of the motor. The intake openings in one end closure are substantially in alignment with the exhaust openings in the opposite end closure.

As shown in FIG. 1, the end closures are spaced a short distance from the free ends of the fan blades 19 and 21. Positioned in this space at each end of the rotating member 16 are baffles 25 and 26 shown separately in FIG. 5. Each baffle may be held in position in any conventional manner and is herein shown as held between the frame 6 and end closures 9 and 11. Each 'baflle 25 and 26 is provided with cutouts 27 in the periphery thereof which permit passage of the throughbolts 12. The bafiles in effect divide each end of the motor frame into inner compartments 29 and 30 and outer compartments 31 and 32. Each bafile is also provided with a central opening 33 which (when positioned in the motor frame) is in alignment with the fan blades. The outer peripheral surface portion of the baflle is cup-shaped except at a relieved portion 34. As shown in FIGS. 1 and 6, at the right hand end of the motor, this relieved portion 34 is in alignment with the exhaust opening 23. Since the exhaust opening at the opposite end or left hand end (in FIGS. 1 and 6) of the motor frame is on the opposite side of the center line of the motor the relieved portion of the baffle 25 is also in alignment with the exhaust opening 26.

In operation when the rotor is revolving, the fan blades 19 and 21 draw air in through the intake ports 22 and 24 in both ends of the motor through the central opening 33 in each bafiie. The air is then thrown outwardly by centrifugal force into the cupped portion of the inner compartments 29 and 30 at each end of the motor. A major portion of the air is then discharged through their respective exhaust openings at the same end of the motor. However, because of the alternate location of the exhaust openings at opposite ends of the motor, a portion of the air flows longitudinally through the air passages between the stator laminations and the recesses in the interior peripheral surface of the motor frame. The arrows in FIGS. 1 and 6 indicate the air flow as it passes longitudinally through the motor. This air flow is due to the pressure differential at the exhaust openings at either end of the motor frame. Since the air pressure on the side of the motor which is exposed primarily to the discharge port is at a lower pressure than the air pressure on the side of the motor blocked from the discharge port, there is a tendancy for a portion of the air to flow longitudinally through the motor providing a cooling effect along the longitudinal length of the motor.

With this arrangement of bafiie and longitudinal passageways, a more complete ventilating of the motor is possible than was possible in the prior art ventilating systems. With this ventilating system all portions of the motor are exposed to cooling air. Because of this improved ventilation system, applicants assignee has been able to utilize less materials without increasing the operating temperature of their motors while at the same time improving the operating characteristics. Furthermore, the expensive casting procedure required for the center discharge ports has been eliminated. Additionally, because of the improved ventilating system, lower air velocities are possibilities with the resultant lower noise levels.

Although only one embodiment of the subject invention has been herein shown and described, it will be ohvious to those skilled in the art after reading this description that other modifications are possible and it is intended that all such modifications which fall within a reasonable interpretation of the appended claims be covered.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A dynamoelectric machine including an enclosure comprising: a stationary member; a rotating member having fan blades on opposite ends thereof; an end closure at each end of said machine spaced from said rotating member, each end closure having air intake and exhaust openings therein with the exhaust opening in one end closure being in substantial alignment with the intake opening in the other end closure; 21 baffie located in the spaces between said rotating member and said end closures and dividing said spaces into separate inner and outer compartments, said bafiies having a central opening adjacent said fan blades and in air communication with said intake openings and having peripheral openings in air communication with said exhaust openings for permitting the circulation of air from the inlet at each end of said motor through the exhaust at the same end of said motor; and an air passage defined by said enclosure and one of said members connecting opposite inner compartments for permitting the flow of air from the inlet at each end of said motor through the exhaust at the Opposite end of said motor.

2. The dynamoelectric machine set forth in claim 1 wherein the stationary member is composed of a plurality of circular laminations stacked together with at least a pair of cir-cumferentially spaced flats on the outer peripheral surface thereof, said flats and the inner peripheral surface of said enclosure defining said air passages.

3. The dynamoelectric machine set forth in claim 1 wherein said intake and exhaust openings are positioned in the lower underlying surface of said end closures.

4. The dynamoelectric machine set forth in claim 2 wherein said air passages are in alignment with the inlet opening at one end of said motor and the exhaust opening at the opposite end of said motor.

5. The dynamoelectric machine set forth in claim 2 and further comprising longitudinal recesses in the inner peripheral surface of said enclosure aligned with said flats to define air passages for the longitudinal flow of air through said machine.

References Cited UNITED STATES PATENTS 1,030,556 6/1912 Williamson 310-58 2,260,042 10/1941 McMahan 310-58 2,500,971 3/ 1950 Wieseman 310-58 2,545,855 3/1951 Luenberger 310-58 2,929,944 3/1960 Shewmon 310-58 3,027,470 3 1962 Atherton 310-59 3,184,625 5/1965 Farison 310-68 3,243,617 3/1966 Cunningham 31068 3,253,167 5/1966 Bates 310-68 I. D. MILLER, Primary Examiner. L. L. SMITH, Assistant Examiner. 

1. A DYNAMOELECTRIC MACHINE INCLUDING AN ENCLOSURE COMPRISING: A STATIONARY MEMBER; A ROTATING MEMBER HAVING FAN BLADES ON OPPOSITE ENDS THEREOF; AND END CLOSURE AT EACH END OF SAID MACHINE SPACED FROM SAID ROTATING MEMBER, EACH END CLOSURE HAVING AIR INTAKE AND EXHAUST OPENINGS THEREIN WITH THE EXHAUST OPENING IN ONE END CLOSURE BEING IN SUBSTANTIAL ALIGNMENT WITH THE INTAKE OPENING IN THE OTHER END CLOSURE; A BAFFLE LOCATED IN THE SPACES BETWEEN SAID ROTATING MEMBER AND SAID END CLOSURES AND DIVIDING SAID SPACES INTO SEPARATE INNER AND OUTER COMPARTMENTS, SAID BAFFLES HAVING A CENTRAL OPENING ADJACENT SAID FAN BLADES AND IN AIR COMMUNICATION WITH SAID INTAKE OPENINGS AND HAVING PERIPHERAL OPENINGS IN AIR COMMUNICATION WITH SAID EXHAUST OPENINGS FOR PERMITTING THE CIRCULATION OF AIR FROM THE INLET AT EACH OF SAID MOTOR THROUGH THE EXHAUST AT THE SAME END OF SAID MOTOR; AND AN AIR PASSAGE DEFINED BY SAID ENCLOSURE AND ONE OF SAID MEMBERS CONNECTING OPPOSITE INNER COMPARTMENTS FOR PERMITTING THE FLOW OF AIR FROM THE INLET AT EACH END OF SAID MOTOR THROUGH THE EXHAUST AT THE OPPOSITE END OF SAID MOTOR. 